Linear polymers of carbon monoxide with one or more olefinically unsaturated aliphatic compounds, that comprise polymer units originating form carbon monoxide on the one hand and the polymer units originating from the olefinically unsaturated compounds on the other hand which occur in a substantially alternating arrangement. These linear polymers of CO and olefinically unsaturated compounds can be prepared by contacting the monomers at an elevated temperature and pressure with a catalyst composition containing a Group VIII metal and a phosphorus monodentate ligand with the general formula (R.sub.1).sub.3 P or a phosphorus bidentate ligand with the general formula (R.sub.1).sub.2 P-R-P(R.sub.1).sub.2 in which general formulae R.sub.1 represents a monovalent hydrocarbon group and R is a hydrocarbon bridge group.
For some applications it may be desirable to have such linearly alternating polymers in which optionally substituted phenyl groups are present as side groups linked to the main chains. Attempts to prepare such polymers using the above-mentioned catalyst compositions starting from a monomer mixture that in addition to carbon monoxide contains one or more optionally substituted styrenes have hitherto been unsuccessful. Although these catalyst compositions are suitable for the preparation of linear alternating polymers of carbon monoxide with one or more olefinically unsaturated aliphatic compounds, they have been found to be unsuitable for the preparation of linear alternating polymers of carbon monoxide with one or more optionally substituted styrenes.
In the course of an investigation by the applicants into these alternating polymers it has now surprisingly been found that starting from monomer mixtures which besides carbon monoxide contain one or more optionally substituted styrenes, linear polymers can be prepared in which the units originating from carbon monoxide on the one hand and the units originating from the optionally substituted styrenes on the other hand occur in a substantially alternating arrangement, provided that in the above-mentioned catalyst compositions the phosphorus mono- or phosphorus bidentate ligand is replaced by a nitrogen bidentate ligand in which an (R.sub.1)N group is present, the nitrogen atom of which is linked exclusively via a non-aromatic double bond to a carbon atom of a hydrocarbon bridge group R and in which, moreover, either an (R.sub.2)N group is present, where the nitrogen atom of which is linked via a double bond to a carbon atom of the bridge group R, or an (R.sub.2)(R.sub.3)N group, where the nitrogen atom of which is linked via a single bond to a carbon atom of the bridge group R, where R.sub.1 in the aforesaid groups has the previously indicated meaning, and R.sub.2 and R.sub.3 are identical or different hydrocarbon groups, optionally corresponding with R.sub.1. Catalyst compositions containing a Group VIII metal and a nitrogen bidentate ligand as described above are novel.
In the course of the applicants' research into these alternating polymers it has also been surprisingly found that suitable catalyst compositions for the preparation of linear polymers of carbon monoxide with one or more olefinically unsaturated aliphatic compounds can be obtained by incorporating as bidentate ligand in the aforesaid catalyst compositions a phosphorus bidentate ligand corresponding substantially as regards to structure with the above-described nitrogen bidentate ligand, but differing from it by both the nitrogen atoms being replaced by phosphorus atoms. Catalyst compositions containing a Group VIII metal and a phosphorus bidentate ligand of this kind are also novel.
In view of the favorable results obtained in the polymerization of carbon monoxide with one or more olefinically unsaturated aliphatic compounds using the novel catalyst compositions containing a phosphorus bidentate ligand, the applicants also tested catalyst compositions for the same purpose in which the phosphorus bidentate ligand was replaced by a phosphorus nitrogen bidentate ligand, and with regards to structure, the phosphorus nitrogen bidentate ligand corresponded substantially with the above-described phosphorus bidentate ligand, but differed from it by one of the phosphorus atoms being replaced by a nitrogen atom.; The results obtained in this part of the investigation were relatively disappointing. Although it was possible, starting from a mixture of carbon monoxide with one or more olefinically unsaturated aliphatic compounds, to obtain linear alternating polymers using these catalyst compositions containing a phosphorus nitrogen bidentate ligand, the activity of these catalyst compositions was far less than that of the novel catalyst compositions containing a phosphorus bidentate ligand.